Rock drill



.July 24, 1934. J Q CURTIS y 1,967,502

ROCK DRILL l Filed May 26', 1935 2 Sheets-Sheet l JOHN C, CL//eT/.S

INVENTOR na k BY ATTORNEY July 24, 1934. 1 ct CURTIS 1,967,502

n ROCK DRILL Filed May 26, 1935 2 sheets-sheet 2 Big5 JOHN CfC//e775 INVENTOR Patented July 24, 1934 ROCK DRILL John C. Curtis, Gareld Heights, Ohio, assignor` to The Cleveland Rock Drill Company, Cleveland, Ohio, a corporation of Ohio Application May 26, 1933, Serial No. 673,051

11 Claims. (Cl. 121-9) This invention relates broadly to rock drills, but more particularly to rock drills equipped with a fluid actuated feeding mechanism.

Heretofore rock drills equipped with a fluid lactuated feeding mechanism were provided with a device permittingtol reduce the feeding power of the mechanism at the will of the operator. For instance, when rotative movement of the cutting tool became restrained, it was possible to reduce the power of the feeding mechanism, by venting some of the pressure fluid from the mechanismA tothe atmosphere. No provisions were made to reduce the force of the blows distributed to the cutting tool by the working piston. With Ysuch a construction, even though the feeding power of the mechanism was reduced, the cutting tool Ywas still driven deeper into the material. To prevent this undesirable feature, the operator wascompelled to bleed the feeding mechanism,

'sufficiently to prevent the hammer from distributing its blows to the cutting tool. These blows, however, were distributed to the frontportion of the machine, thus causing the breakagev thereof and increasing the cost of operation.

rli'he main object of this invention is to provide means whereby the feeding power of the feeding mechanism together with-the force of the blows distributed to the cutting tool, may be reduced at the will of the operator.

` i Other objects more or less ancillary to the foregoing, and the manner in which the object is realized will appear in the following description, considered in connection with the accompanying drawings, set forth the preferred embodiment of the invention.

In the drawings: 1

Fig. 1 illustrates a longitudinal cross sectional view of a rock drill of the stoper type embodying the invention,` the parts 4thereof being shown in 'normal operating position. Y

Fig. 2 vis an enlarged cross sectional view taken in a plane indicated byline 2-2 in Fig. 1, showing the Valve in closed position.

Fig. 3 is a view similar to Fig. 1, illustrating the dilerent parts moved into another position.

FigA is a view similar to Fig. 2, illustrating the Valve in open position. v l

Referring to the drawings in which like characters designate corresponding parts throughout the several views, 10 represents the cylinder of a rock drill, having a piston 11 reciprocably mounted therein. Mounted into the front end of the cylinder 10, there is -a front housing adapted to siidabiy but non-rotatably receive the shank 12 of a cutting tool upon which the piston 11 is free to deliver its blows. The back end of the cylinder 10 is enlarged to accommodate a valve block 13, and the cylindrical portion 14 of a head l5. Reciproca'bly mounted within the valve block 13, there isra uid actuated valve 16 capable of engagement with opposed annular valve seats 17, for controllingthe admission of the pressure uid into the cylinder. The Valve block 13 is provided with a plurality of passages 18 leading from one face of the valve into the rear end of the cylinder. Similarly the cylindrical portion 14 of the head 15, is provided with a plurality of passages 19 leading from a chamber 20 to the valve 16, and other passages 21 leading from the valve 16 into Vthe front end of the` cylinder. To permit the exhaust of the pressure fluid from the cylinder, the latter is equipped with a duality of exhaust passages 22, opening into a deflecting exhaust port 23.

Formed within the back head 15, there is a tapered socket adapted to receive the correspon-ding end of a handle 24, secured therein by means of a nut 25. This handle may be grasped by the operator for rotating the machine assembly and consequently rotating the cutting tool.

Within the handle there is provided an enlarged lubricant reservoir 26, which may be illed at will by removing a screw threaded plug 27.

Disposed near the outer end of the handle 24, the latter is formed with a screw threadedbore 28, the bottom thereof constituting a chamber 29. Secured in screw tight engagement within the bore 2S, there is a plug 30 adapted to slidably receive the stem 31 of a valve 32. One end of this stem is formed with a knob 33 protruding from the plug 30, upon which manual pressureY may be applied to operate the valve. Adjacent the valve 32, the plug 30 is formed with a valve seat formed by the outer edge of an enlarged Vorifice 34, which is in constant communication in a spool Valve 38. IThis chamber is closed at one end by a screw threaded plug 39 adapted for engagement with the valve 38 to limit the stroke lthereof in one direction. Interposed between one ,end of the valve 38 and the bottom of the cham- Ychamber 37 having reciprocably mounted thereber 37, there is a compression spring 410,V the purpose of which will be explained later.

Secured to the rear end of the head 15, there is the feeding mechanism comprising a feed tube 41 having a piston and piston rod 42 and 43, slidably mounted therein. Since this mechanism is common to tools of the type described, no further explanation is thought necessary.

Rotatably mounted within the head 15, there is a throttle .valve 44 formed v,with a bore.45 through which: pressur'efluid 'mayiiberladmittiedkf from its source" of supply. Leading from the bore 45 to the circumferential valve of the-throtetle valve, there is a plurality of radially disposedY passages 46, 47, and 48. The passage 46 is capable of communication with the chamber 28 for??y admitting pressure fluid therein, while the pas-- sage 47 is capable of cornn'iuni'cationwithlthei` interior of the air feed cylinder 41 th'rougli.'pas-` sage 49, annular groove i), and passage 51. Similarly, the passage 48 is capablefoffcommunicae tion with the Valve chamber 37 through the passage 52, annular groove 53 and passage 54.' Again thislvalve chamber 37 -is:inconstantcoinrnunicagtion: Fwith the chamber f29formed-in1the handle 24,through1arpassage 55, annular :groove 56; and. passage e515 I ieadingafrom the 'fair-feedlcylinder l 41 into=thefvalvecharnber; `there Yis-apassage 58. Topermit-the communication :of-thisflast. passage witlrthe -rearend-of fthe cylinder 10,-.-the valve3isformedgwith .an annular .groove 59,". thus affording;- the communication-.oi the pasr sage--58lwith a-passage-GO, annulargroove 61, andY passage c62, A The lubricant from. the'k resevoi 26 may4V be admitted intrrtleV 'throttle valve -bore 48' through va .passage- 63".

Duringthefnorinalfoperation of the. machine,` assumingfthe'throttle valve 44 vto.be-.1'3ositioned as' illustrated in Figsl', pressure fluid is adrnit'tedinto the chamber V2() vto be distributed by the valve 16 y into botl'fends offth'e cylinder 10 `to 'actuat the piston 11T Whenthe valve-16`is positioned' as uillustrated'i the drawings; pressure fluid is 'adi mitted into-theirontL-end of the cylinder to drive 'the 4'piston 1v1 rearwardly; l Ddrin'g'the "rari Ward' travell`o`f`thepis'ton, tl'e'exhalu's' ports 22Nn will'be covered by the "latter, 1 thus compressing' tne'atmpsph'ere "in tn'erearend" ofthe cyiderg andcreatgpess'' the Valve-'16. `The `Op`` erat'o'n andsniftgor tnis'valve beirgrtne' saine" as theroperaticn of-"th'e vaivddescripd pending application "Serialg'No l5'73','931",' no' furr ther explanation 'is' thought necessaryot-her than" mentining' "tle fa'ct that "the'vaive' 16"'is 'thrown' rearwardly' byA f compression" admitted'i thereto' tnrm'ghftrie"passages,W is." Whenwhe'valve leds shifted' 'in its rearrrfost "pp'sitdm mptiv'e- 'Huid is' J5 admitted'-" lhito UheWreaV'end" of the cylin`dei""" througncthe passages v'i8 to Adrive 'thepiston 11 Y forwardly; thus "limiting: the' "rearward strokpf" the'fpis'cdrr.- The'valveis'designed'in suenaman-r ner as `to` return" the 'piston' forwardly'justbefore C@ ,.the'lla'tter reaches'the'valvebocll: '13, permitting thereby*r the stroke of the pisto'nt'beabout'equal to tn'efr'ee'space'intne'cylinder: Duringthe nerr mal operationfof A"the machina pressure fluid 'is' also"admit'te`d in'to the' air" feed'cylinder' from Ghfthehrottle valve '44,; through "the passages'47` and 49, annular groove "f'and'passage 51, to act 'on' the feedpistc1r42'a'n'ddrive'the'machine' upwardly A'or 'tcwardwn'ef' w'crkl simultaneously," pressure' 'iuid`is` y'adn/f1tted 4"from the 'throttle'valve main the 'valve 'char'nber .3 7 tlifiough'the passages '48 and'5`2f` annular 'groove' 53',"and"pass'age 54,' to act" on "thevalve 38"and'-`maintair the 'latter toward" the `right,f.a`gainst Athe tension" of fthe" spring' 40," or in the position -illustratedfinliigs 1.' When' 3'5;.1the.valve isin` this positimit Ywillfb seen'that the communication of the passage 58 with the port is shut off, thus preventing pressure uid to flow from the air feed cylinder into the rear end of the cylinder 10. In this position of the valve 38 the hand operated valve 32 is maintained against its seat by the tension of the compression spring 36, thus. preventing the communication of the .chambaN Zawith the atmosphere throughthe passage 35."

Whenwthe cutting tool becomes stuck in the S5 drilled hole, manual pressure may be applied on the knob 33 to open the valve 32. Pressure fluid stillidmitted into the valve chamber 37 will now escape to the atmosphere through the passage 55,,annulargroovezjpassage 57, chamber 29, and .Ipassages 34fand35", thus relieving the pressure acting on the valve 38, and permitting the 'shiftinggtltereoftoward the left by the tension of the spring. 40. In this position of the valve 38, pressure'iiuid will be admitted into the back of thecylinder .10 .throughtherpassage,4 Avalvev annular groove EWI-.passage .60; annular. groove 61, and vpassagew62'f.. This add-iticnal.-arnountot.V pressure .fluidadmittedlinthe rearwend of Lthef cylinder f 10 will,v during` .the rearward movement 1005 of th'epistongbe compressedr'b'y` the piston and.- cause a premature shiftinggof the valve-16; The premature shifting., of Vth'elvalv'e will permit the .L admission of thepressure iiuid into the' rear end i of the cylinder, thus'v preventin'g`,`a completel 1053,; stroke" ofthe pistoni, ,and consequentlyA reducingthe frce of the blows deliveredtotnefcuttng;Y tool. Duringthe'lforward:movement ofthe .pis-

ton; ythe latter. will uncoverone 'Lof `the'exhaust"" passages 22`permitting"there`by thepressure'f'lui'd 110,455 in the 4rear of the cylinder 'and"consequent1y a"' portion" of the "motive "fluid from" theairied cylinder to" exhaust to atmosphere? thus' reduc-V`v ing theeedingipower 'ltwillibe'seen thatth'e" f feeding" power 'of "the" feeding'.'mechanism4 vrea" '11535,

ducedeveryv timethfepislton' 'uncovers-'the exhaust`r` passages, while thetstrokeofthepistoir isli'nited'AL by the pressure fluid flowing"frorrr the '-air'efef'ed 4' I cylinder."

When it is `desiredto;resumethe#normaloper 120%, ation' of the machine,"'thefoperatorJrnay*relieve the-jpressureeprevicusly applied or'r the' know-33; thus perihitting:V the Valve 32 to" be shifted# b'y closing the passage 34. f' TheFpressure'admitited 1255i into:thesvalvfchamberB through" thefpassage154f willi again shiftl the valvel -towardfthe*riglitrras previouslyexplained- Aitirfoug'hf;tnfroregoing 1 deseriptonsisl--nec sarily of-l `afdetailedfcharaeter; 'ordeiflto' co pletely set forth the invention, it is tome-funden stood that the specific terminologyF-islnbttrtendedi to be Y' restrictive "-orconiiinlg iandflit Lis, to i be' fur# ther`understoodffthat'various 'rearrangements of@v f' parts andrnrodnationfof 1"theirstructuraiudetair :1,13 5, L.

may be resorted to withoutdeparti-ii'g'fromithev `scop'efior spirit Softhe1inventionas'\herein"claimed I claimt 2; In aro'ckr drill; thefcornbination of avcyli-nv der "having: a fluid "actuated-f pistonmreciprocable therein',y of a tool adapted'to receive-f the striking f.. blows -ofv saidk piston, Kofafluidgactuated feeding... y mechanism` forsaidrock drilladapted toifeed said: 350;;

tool to the work, and of means for reducing the feeding power of said mechanism and simultaneously reducing the striking power of said piston on said tool.

3. In a rock drill, the combination of a cylinder having a iiuid actuated piston reciprocable therein, of a tool adapted to receive the striking .blows of said piston, of a fluid actuated feeding mechanism for said rock drill adapted to feed said tool to the work, of a throttle valve for controlling the admission of the pressure fluid into said cylinder and said mechanism, and of means independent of said throttle valve for reducing the feeding power of said mechanism and reducing the striking power of said piston on said tool.

4. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a fluid actuated feeding mechanism for said rock drill, of means for controlling the admission of the pressure fluid into said cylinder to actuate said piston, and of other means for permitting or preventing an additional amount of pressure fluid to be admitted from said feeding mechanism into one end of said cylinders.

5. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a valve block having a` fluid actuated valve reciprocable therein for controlling the admission of the pressure fluid into said cylinder to actuate said piston, the shifting of said valve in one direction being responsive to the action of fluid compressed by said piston within one end of said cylinder, of a throttle valve for controlling the admission of the pressure iiuid into said valve block, and means independent of said fluid actuated valve and said throttle valve for controlling the admission of a supplemental amount of pressure fluid into said one end of said cylinder to cause the premature shifting of said valve into said direction, reducing thereby the length of the stroke of said piston.

6. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a fluid actuated valve for controlling the admission of the pressure fluid into said cylinder to actuate said piston, the shifting of said Valve in one direction being responsive to the action of uid compressed by said piston within one end of said cylinder, a fluid actuated feeding mechanism for said rock drill, means for admitting motive fluid into saidmechanism, and means independent of said valve for admitting pressure fluid from said feeding mechanism into said one end of said cylinder to cause a premature shifting of said valve into said direction, reducing thereby the length of the stroke of said piston, the pressure fluid from said feeding mechanism being subsequently exhausted from said cylinder, thus reducing the feeding power of said feeding mechanism.

7. In a rock drill, the combination of a cylinder having a uid actuated piston reciprocable therein, a fluid actuated feeding mechanism for said rock drill, a throttle valve for controlling the admission of the pressure fluid into said cylinder and feeding mechanism, and a hand operated auxiliary valve for controlling the exhaust of the pressure iiuid from said feeding mechanism into said cylinder, said exhaust to the atmosphere being further controlled by said piston within said cylinder.

8. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, a fiuid actuated feeding mechanism for said rock drill, means for admitting pressure fluid into said cylinder and feeding mechanism, a passage affording communication from the former to the latter, and means for closing said passage without affecting the normal operation of the rock drill, said means being capable of position to open said passage, permitting thereby pressure fluid from said feeding mechanism to be admitted into said cylinder.

9. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a fluid actuated feeding mechanism for said rock drill, of means for exhausting the pressure iiuid from said feeding mechanism into said cylinder, said means comprising a passage, an exhaust controlling valve subjected to the action of the pressure fluid admitted thereon for normally closing said passage, a port for exhausting the pressure iiuid acting on said exhaust controlling valve for permitting vthe shifting of the latter in a position for opening said passage, and means associated with said exhaust controlling valve for shifting and holding the latter in the open position.

10. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a iiuid actuated feeding mechanism for said rock drill, of independent passages for admitting pressure uid into said cylinder to actuate said piston and into said feeding mechanism to operate the latter, and of means for admitting a supplemental amount of pressure iiuid into one end of said cylinder and simultaneously exhausting an equal amount of pressure fluid from said feeding mechanism.

11. In a rock drill, the combination of a cylinder having a uid actuated piston reciprocable therein7 of a fluid actuated feeding mechanism for said rock drill, of unitary means for controlling the normal admission of the pressure fluid into said cylinder and said feeding mechanism, and of other means for controlling the admission of a supplemental amount of pressure fluid into said cylinder and simultaneously controlling the exhaust of an equal amount of pressure uid from said feeding mechanism.

JOHN C. CURTIS. 

